Trial Confirms Benefit of SLIT for Dust Mite Allergy

By Reuters Staff

September 17, 2020

NEW YORK (Reuters Health) - A sublingual tablet containing house dust mite (HDM) extract is effective for reducing allergic rhinitis symptoms (AR), a new phase-3 trial shows.

Over 12 months of treatment, patients randomized to the 300 index of reactivity (IR) sublingual immunotherapy (SLIT) tablet, developed by Stallergenes Greer (Antony, France), also used significantly less medication for their symptoms and had a better quality of life. However, there were more serious adverse events in the active-treatment group.

HDM allergens are nearly impossible for allergic individuals to avoid, and only symptomatic treatments for AR are available, Dr. Pascal Demoly of Hopital Arnaud de Villeneuve in Montpellier, France, and colleagues note in the Journal of Allergy and Clinical Immunology.

Trials of the 300 IR tablet, containing Dermatophagoides pteronyssinus and D. farinae extract in a total allergenic activity ratio of 1:1, have been conducted in Europe, Canada and Japan, and it has been approved for commercialization in the Asia-Pacific region. The new trial was intended to confirm the findings in a broader array of patient populations across the U.S., Israel, Russia, Canada and Europe.

The trial included a five-week placebo run-in period, after which those with an average Total Combined Score (aTCS) of at least 5 out of 15 were randomly assigned to HDM allergen immunotherapy (AIT) or placebo for one year. The full analysis set included 1,476 patients.

During the four-week primary evaluation period, the relative mean least squares difference in aTCS between the active-treatment (3.62) and placebo (4.35) groups was -16.9%, a significant difference above the pre-specified cutoff of -15%.

"This relative difference of -16.9% is greater than that associated with some types of symptomatic medication (such as leukotriene receptor antagonists and oral antihistamines) used to treat perennial AR," Dr. Demoly and colleagues note.

Both groups showed a decline in aTCS over time, which was greater with active treatment, showing a significant difference from placebo beginning with the third treatment month.

Patients on HDM AIT had significantly less nasal pruritis, sneezing, rhinorrhea, nasal congestion, ocular pruritis and tearing than the placebo group during the first four weeks of treatment. In the 300 IR group, 72.2% had no worsening of rhinitis during the primary treatment period, versus 61.4% of the placebo group.

Overall scores on the Standardized Rhinoconjunctivitis Quality of Life Questionnaire, and within each individual domain score, showed significantly more improvement by the end of the treatment period in the patients given 300 IR.

Treatment-emergent adverse events (TEAEs) were reported by 70.1% of patients on active treatment and 54.9% of the placebo group. Mild to moderate application-site reactions were the most commonly reported TEAEs associated with the tablet.

In the active-treatment group, 12.4% withdrew from the study prematurely due to TEAEs, compared to 2.1% of the placebo group. Twenty-four serious TEAEs were reported by 21 patients on active treatment, and nine patients in the placebo group reported 11 serous TEAEs.

"Our present results confirmed that a 12-month course of treatment with a 300 IR sublingual HDM tablet was effective for the treatment of moderate-to-severe HDM-induced AR (with or without concomitant mild controlled asthma). The safety profile was consistent with the literature data on sublingual HDM AIT, with no newly identified or unexpected risks," they conclude.

Dr. Demoly and other study authors report financial relationships with Stallergenes Greer, which funded the study and paid for preparation of the manuscript.

Dr. Demoly was not available for an interview by press time.

SOURCE: https://bit.ly/2RkCQpf Journal of Allergy and Clinical Immunology, online September 2, 2020.

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